The question involves a few layers of consideration. Catholic teaching isn’t uniform, though many folks think it is. The heaviest layer of teaching is called dogma, Greek for “what seems right.” Dogma is an infallible teaching of the church and will not be revoked. Because of its gravity, your pastor can’t up and declare a dogma nor can your local bishop. The formal promulgation (official publishing) of a dogma can be advanced only by an ecumenical council of the church which includes the pope or by the pope himself.

Dogmatic teaching acquired its heft at the First Vatican Council in 1869-1870 and was reiterated in the 1917 Code of Canon Law. At that time it was determined that dogma must meet three conditions. First, it must be rooted in scripture or post-biblical tradition and be divinely revealed. That means at the very least that it’s time-tested, not sprung out of yesterday’s news or today’s political situation. Second, the church must explicitly propose it as dogmatic. That protects us from the rogue cleric, theologian, or small-faith-sharing-group leader who makes a lone interpretation. Third, such proposals are made in solemn decrees or universal teachings. So you don’t have to read every book a pope writes—worthy though that may be—to be sure you’re not missing a dogma slipped into chapter six.

It would be helpful if there were a page devoted to dogmatic teachings on the Vatican website so there would be no mistaking a simple teaching from an unassailable one. Because formal and deliberate rejection of a dogma is considered a heretical act, it could be vital to your interests to know for sure whether you’re crossing a sensitive line or an irrevocable one.

Interestingly, the Congregation for the Doctrine of the Faith has declared that dogmas are influenced by “the changeable conceptions of a given epoch.” While the central meaning of a dogma cannot change, its expression can and must be reevaluated in each age to preserve the clarity and applicability of its revealed truth (see the document [link below] Mysterium Ecclesiae, 1973).

Every dogma is a doctrine (“teaching”) of the church, but not all doctrines are dogmas. So the long answer to the question is: If a doctrine isn’t a dogmatic teaching, yes, it can change. The preferred mode of change is development rather than a subsequent erasure of an earlier teaching outright. How doctrines “develop” is a topic for another time—and the sure instigator of many useful arguments.

Elated or Frustrated?

"Religious life ought to promote growth in the Church by way of attraction. The Church must be attractive. Wake up the world! Be witnesses of a different way of doing things, of acting, of living! It is possible to live differently in this world.” -- Pope Francis